Super Bowls: serving bowl size and food consumption.

To the Editor: Obesity has been linked in part to the expanding portion sizes of prepackaged or preserved foods. However, adults frequently serve themselves the food they will eat for a meal or snack. We investigated how the size of serving bowls influences how much food a person decides to serve and consume in a natural environment. Methods. Graduate students were recruited to attend a Super Bowl party at 5:30 PM. On arrival, 40 individuals orally consented to participate in an institutional review board– approved study in which they " may be asked questions about food and commercials in party environments, such as at a Super Bowl party. " No reference was made to the hypotheses being examined. Each participant was led in an alternating order to 1 of 2 identical buffet tables on opposite sides of an adjoining room and asked, " Would you care for some snacks before the game? " – had identical amounts of high energy density snacks (assorted roasted nuts and a pretzel/ chip variety mix, both approximately 5.26 kcal/g). On one table these snacks were offered in 2 large (4-L capacity) serving bowls. On the second table, an equal quantity of the same 2 snacks was offered in 4 medium (2-L capacity) serving bowls that were otherwise identical to the larger bowls. Participants served the snack mix to themselves on 10-inch plates using a 1-cup serving scoop. Immediately following their self-serving, a research assistant blinded to the purpose of the study weighed the plate. The participant was then led to a table to watch the game. Beverages were not available until after the food was served. After the last participant had taken a serving, all food was removed. One hour later, each participant completed a questionnaire. Each plate was collected and plate waste was recorded and subtracted from how much each had initially taken. Participant characteristics between the study groups were compared using t tests. The volume of food served and eaten was analyzed with a 2-way analysis of covariance, which used bowl size and sex as factors between participants. Body mass index (calculated as weight in kilograms divided by the square of height in meters), body weight, hours since prior meal, age, and education were used as covariates. A power analysis indicated a power of 0.91 for detecting an effect size of 0.50 at the 5% confidence level with a sample of 20 …